N,N-Dimethylaniline → Sulfurous Acid

Participants

Reaction Steps

The effluent gas from absorber section 5 is impoverished in sulfur dioxide and enriched in gaseous dimethyl aniline and passes sequentially through sulfurous acid scrubbing section 9 and sulfuric acid scrubbing section 10 and leaves scrubbing section 10 through line 18 very low in sulfur dioxide content and free or substantially free of absorbent. In sulfurous acid scrubbing section 9, sulfur dioxide gas and liquid aqueous ammonium sulfate solution withdrawn from the bottom of the regenerator are separately fed into the lower and upper portion respectively of scrubber section 9 beneath the lowermost tray and above the uppermost tray respectively through lines 19 and 20 respectively. Liquid water per se may be supplied into the upper portion of the sulfurous acid-ammonium sulfate scrubbing section 9 through line 22 for the sulfurous acid production in the event additional water is needed to supplement the water introduced into this scrubbing section in the aqueous ammonium sulfate solution, and to maintain the water balance in the process. The uprising sulfur dioxide gas is dissolved in the water of the descending current of aqueous ammonium sulfate solution to form a dilute aqueous solution of sulfurous acid and ammonium sulfate which flows downwardly from tray to tray in scrubber section 9. The presence of the ammonium sulfate in sulfurous acid scrubbing section 9 results in a considerably enhanced dissolution of the SO2 gas in the water to from sulfurous acid as is previously disclosed herein. The uprising effluent gas bubbles through the descending current of thus-formed dilute sulfurous acid- and ammonium sulfate-containing solution which flows downwardly from tray to tray in scrubber 9, and a major portion, i.e. more than 50 percent, and typically more than 90 percent of the gaseous dimethyl aniline present in the gas is removed from the gas in scrubbing section 9 by reaction with the sulfurous acid in the presence of the ammonium sulfate to form dimethyl aniline sulfite. The liquid aqueous sulfurous acid-and ammonium sulfate-containing scrubbing solution also containing the thus-formed dimethyl aniline sulfite is withdrawn from the lower portion of scrubbing section 9 through line 62 and passed to collection tank 63.

Provenance & Evidence